Means to through-connect and cancel the through-connection of crosspoints in a crossbar switch



April 22. 1969- K. STRUNK 3,440,581 T AN -COHNE'CTION MEANS TO THRGUGH-CONNEZC D CANCEL THE THROUGH Filed Aug.

OF CROSSPOINTS IN A CROSSBAR SWITCH Sheet illlltllf I Filed. Aug. s, 1966 April 22, 1969 K. STRUNK 3,440,581

MEANS TO THROUGH-CONNECT AND CANCEL THE THROUGH-CONNECTION OF CROSSPOINTS IN A CROSSBAR SWITCH Sheet 3 of4 April 22.1969 5mm 7 3.440.581

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April 22, 1969 K. STRUNK 3,

MEANS '10 THROUGHCQNNECT AND CANCEL THE THROUGH-CONNECTION OF CROSSPOINTS IN A CROSSBAR SWITCH Filed Aug. 5, 1966 Sheet 4 of 4 United States Patent 3,440,581 MEANS T0 THROUGH-CONNECT AND CANCEL THE THROUGH-CONNEQTION 0F CROSSPOTNTS IN A CRUSSBAR SWITCH Kurt Strunk, Markgroningen, Germany, assignor to International Standard Electric Corporation, New York, NRC, a corporation of Delaware Filed Aug. 3, 1966, Ser. No. 569,955- Clairns priority, application Germany, Aug. 10, 1965, St 24,244 Int. Cl. H0111 67/14 US. Cl. 3351l2 5 Claims ABSTRACT OF THE DISCLOSURE This invention relates to crossbar switches and more particularly to improved utilization of crosspoints in such switches.

The invention relates, in more detail, to the establishment of through-connections or closures of crosspoints and to the cancellation of previously established connections of crosspoints. in a crossbar switch. An exemplary switch for this purpose incorporates several selecting bars with marking springs and a plurality of holding bar armatures, several contact wires, and a number of contact spring sets for each selecting bar corresponding to the number of holding bar armatures. The contact springs of the contact spring sets are located in a plane perpendicular to the plane of the contact wires, and each contact spring set contains a common follower element (strap).

There are known crossbar switches which have in a common frame a number of vertically arranged holding bars (individual switches) which can take over within said frame different functions either individually or in groups, depending on the kind of systems. A plurality of horizontal selecting bars are associated with the vertical holding bars and each selecting bar bears a number of marking springs, corresponding to the number of holding bars. The bars are pivoted at their ends and can be tilted through their armatures when the respective selecting bar magnet is excited. The marking springs are also tilted correspondingly, associated to each holding bar and fixed to the selecting bars. The holding bar armatures have at the level of each selecting bar a recess into which protrude two guide straps of the contact springs. In the non-operative position the marking springs are located in the centre between the straps. If one of the two selector magnets of a selecting bar is excited the marking springs tilt upward or downward and engage the corresponding straps of the holding bars associated with them. If a holding bar magnet now responds the pertinent holding bar magnet presses the corresponding strap with the aid of the tilted marking springs, and, consequently, moves the contact springs of the respective crosspoint towards the contact wires of the terminating line. After the selecting bar magnet has been switched off, the selecting bar is returned to its non-operative position by a spring force. The marking spring kept by the holding bar does not follow this resetting of the selecting bar,

3,440,581 Patented Apr. 22, 1969 but is bent resiliently. As soon as at a crosspoint a spring set is marked by the corresponding selecting bar and the holding bar armature has been switched, the same selecting bar is available to further mark other holding bars. In the extreme case one single selecting bar can set all holding bars at the mechanically equivalent points, whether the selecting bar is tilted upward or downward. Only by switching off the respective holding bar magnet can the connection be released. That means the holding bar armature returns into its non-operative position, the marking spring is released and rebounds to its straight position while the contacts open at the same time.

The foregoing and similar known constructions share the draw-back that under control of a holding bar only one crosspoint can be actuated, independent of the other crosspoints. This means, if a connection is established, the corresponding holding bar armature must be pressed to the springs for a time period lasting until the connection is released. The armature is not available for any other connection within the respective holding bar during this time period.

It is a primary object of the invention to avoid the foregoing disadvantages by enabling the actuation of the crosspoints subject to control by a holding bar independently of each other, thereby subdividing a holding bar into several electrically separate switching elements. This is achieved, according to a preferred embodiment of the invention by the use, for through-connection and for the release of such a through-connection, of different actuating sequences for the selecting bar and the holding bar armatures. This arrangement causes a mechanical locking of the strap in its through-connected position, or releases said locking, respectively.

According to a first feature of the invention the following steps are used for making a through-connection:

(1) The selecting bar is tilted thereby causing the marking spring to engage the strap in a known (2) The holding bar armature is then pulled up to cause the strap to move over, to through-connect the contact springs and the contact wires and to mechanically lock the strap in this position,

(3) The holding bar armature is released,

(4) The selecting bar is then restored,

and the following steps are followed to release the through-connection:

(1) The selecting bar is tilted in the direction of the mechanically locked strap to cause the marking spring to engage the strap,

(2) The holding bar armature is pulled up,

(3) The selecting bar is restored, whereby the mechanical locking of the strap is cancelled, and

(4) The holding bar armature is released to release the through-connection and to release both the marking spring and the strap.

According to a second feature of the invention the following steps for through-connection are used:

(1) The selecting bar is tilted in the direction of the mechanically locked strap to cause the marking spring to engage the strap,

(2) The holding bar armature is pulled-up to release the mechanical lock on the strap,

(3) The holding bar armature is released, and

(4) The selecting bar is restored.

As only one mechanical actuating element per holding bar exists (holding bar armature) the through-connection of several crosspoints in a holding bar one at a time is possible only when the crosspoints show adhesive properties. Such a method shows substantial advantages, compared to the known ones. In the method according to the invention, for example, a holding bar can be subdivided into several electrically independent switching elements. Consequently, the subdivision of a large switch into several small switch blocks is possible. When applying the method described a cheap crosspoint (a large switch) is available which can be used in groups of small switch blocks (small number of crosspoints).

Theoretically, it is possible by practicing the invention to actuate with each holding bar armature all crosspoints associated with it, independently of each other. The saving of switching means resulting from this possibility is considerable.

The present invention includes arrangements to carry out the steps described. According to an embodiment of the invention another spring 4 is associated with each pair of contact straps, in addition to the marking spring belonging to the armature. This spring is also fixed to the selecting bar and engages, after actuation of the holding bar armature, into a recess of the contact strap marked in such a way that the actuated contact strap remains fixed after the holding bar armature has dropped and the selecting bar has returned to its original position.

According to a further embodiment of the invention an adhesive spring is associated with each individual contact strap, said spring not being fixed to the selecting bar. Each spring touches, under mechanical bias, the pertinent contact strap and being actuated by an element firmly connected to the selecting bar engages, after through-connection of the strap during the restoration of the selecting bar, into a recess of the marked contact strap in such a way that the actuated contact strap remains fixed, after the holding bar armature has dropped.

The invention is now described with the aid of examples, shown on the accompanying drawings, wherein:

FIG. 1 shows a portion of a crossbar switch according to the invention, not actuated,

FIGS. 2 to 5 show steps to through-connect a crosspoint in the portion shown on FIG. 1,

FIGS. 6 to 9 show steps for releasing a through-connection of a pair of switch points, shown in FIG. 1,

FIG. 10 shows a portion of a crossbar switch according to the invention in which an adhesive spring is associated with each contact strap in a perspective view,

FIG. 11 shows a known crossbar switch, schematically, and

FIG. 12 shows a possible crossbar switch, schematically when applying the principles of the present invention.

FIG. 1 shows crosspoints of a holding bar, marked by a selecting bar. The contact straps 1' and 1" are marked by pressure of a marking spring 3 in a known way on the side of the holding bar armature. Besides the marking spring on the armature side another spring 4 is associated with each pair of straps fixed to the selecting bar (not shown on FIG. 1 of the drawing but see FIG. 10). This spring 4 serves to mechanically lock the strap by contact with a recess 7 (FIG. 3). Number 5 indicates the contact springs which penetrate through apertures of the straps and are located opposite to the contact wires 6. Each useable crossbar switch will of course include a number of holding bar armat-ures, selecting bars and associated components.

FIG. 2 shows the first step of the method to throughconnect a switch point. In this example, the selecting bar is tilted so that the marking spring 3 engages the strap 1'. At the same time, the spring 4 touches the strap 1' with a mechanical bias.

During the second step of the method, shown in FIG. 3, to through-connect the line, the holding bar armature 2 is pulled up to through-connect the strap 1 with the aid of the marking spring 3. At the same time, the spring 4 locks the strap 1 in its through-connected position by engaging the recess 7. At this time, the contact springs 5 touch the contact wires 6. A plurality of solutions, depending upon the shape and the position of the recess '7 into which the spring 4 must fit, can be given.

At the next or following step, shown in FIG. 4, the holding bar armature 2 drops.

During the last operation, shown in FIG. 5, the selecting bar is restored, and the marking spring 3 disengages from the strap 1. But the spring 4 remains clamped, locking the strap 1'. Thus the holding bar armature 2 is released and may be used to through-connect a crosspoint, associated with another selecting bar.

FIG. 6 shows the first step involved in releasing the through-connection of a crosspoint. By the first step, the selecting bar is tilted in the direction of the mechanically locked strap 1, so that the marking spring 3 engages the strap 1'.

The second step to release the through-connection is made, as shown in FIG. 7, by pulling-up the holding bar armature 2.

At the next step, shown in FIG. 8, the selecting bar is tilted into its non-operative position, so that the spring 4 cancels the locking of the strap ll. But the marking spring 3 still remains clamped by the holding bar armature 2 having pulled up.

The last step to release the through-connection is shown in FIG. 9, namely the dropping of the holding bar armature 2, whereby the marking spring 3 is released and the strap 1 is also released. Thereby the contact springs 5 are again separated from the contact wires 6.

FIG. 10 shows an arrangement in which an adhesive" spring 4', 4" is associated with each individual contact strap 1', 1". To through-connect a crosspoint the selecting bar 9 is tilted in the direction of the strap to be through-connected, e.g., 1, whereby the marking spring 3 engages the strap. The adhesive spring 4', touching the strap 1 under mechanical bias, is thereby pressed off by the actuating element 8. After the holding bar armature, not shown on the drawing, has pulled up and the therefrom resulting through-connection of the strap 1 the selecting bar 9 is restored. The marking spring 3 remains clamped by the pulled-up holding bar armature and the adhesive spring 4, can now engage into the aperture 7' of the strap 1', because it is no longer held off by the actuating element 8. After the holding bar armature has dropped, the marking spring 3 is released; but the strap 1 remains locked by the adhesive spring 4. To release the through-connection the selecting bar 9 is again tilted in the direction of the locked strap 1, where-by the marking spring 3 engages said strap and the actuating element 8 presses towards the adhesive spring 4'. When the holding bar armature is pulled up, the adhesive spring 4' disengages from the aperture 7' of the strap 1'. When the holding bar armature drops, the through-connection of the strap 1 is cancelled and, after the selecting bar 9 has been restored, the original condition is obtained again.

FIG. 11 shows schematically a crossbar switch as known hitherto, having no subdivision of the holding bars, e.g., 2, into several independent switching elements.

FIG. 12 shows a possibility to subdivide the holding bars of a crossbar switch, when applying the invention, e.g., into three individual switching elements 2, 2", 2.

While the principles of the invention have been described above in connection with specific apparatus and applications, it is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention.

What is claimed is:

1. A crossbar switch for connecting crosspoints and for cancelling connections of crosspoints comprising, a marking spring, an adhesive spring, a contact strap, a selecting bar rotatable to cause said marking spring and said adhesive spring to engage the contact strap, a holding bar, a pair of contact wires, a pair of contact springs, said contact strap being aligned perpendicular to a plane defined by the contact springs, said strap incorporating apertures through which the contact springs protrude and a recess into which the adhesive spring may fit, and said holding bar being movable to cause said adhesive spring to fit into the recess and to lock the contact strap in a fixed position, whereby dilferent actuating sequences of the selecting bar and of the holding bar [armature] may be used to efliect a change in the mechanical locking of the strap and connections between the contact springs and the contact wires.

2. A crossbar switch substantially as claimed in claim 1 in which the selecting bar is tilted to cause the marking spring to engage the strap, the holding bar is pulled-up to cause the contact springs and the contact wires to be through-connected and the strap to be mechanically locked in a position by the adhesive spring, and said adhesive spring maintains the strap in its locked position when the holding bar armature and selecting bar are released.

3. A crossbar switch substantially as claimed in claim 2, in which release of a through-connection includes: tilting the selecting bar in the direction of the mechanical- 1y locked strap and engaging the marking spring into said strap, pulling-up the holding bar armature to cause restoration of the selecting bar whereby the mechanical locking of the strap by the adhesive spring is cancelled, and subsequently dropping the holding bar armature to release both the marking spring and the strap.

4. A crossbar switch as claimed in claim 1, in which the adhesive spring is fastened to the selecting bar and engages an aperture of the marked contact strap in such a way that the actuated contact strap remains fixed, after the holding bar armature has dropped and the selecting bar has been restored.

5. A crossbar switch as claimed in claim 1, in Which the adhesive spring is fastened to an anchor in the switch and is mechanically actuated by an element fastened to the selecting bar, and which, after through-connection of the strap and during the restoration of the selecting bar, engages into an aperture of the marked contact strap in such a way that the actuated contact strap remains in place after the holding bar armature has dropped.

References Cited UNITED STATES PATENTS 2,337,941 12/ 1943 Shepherd 3351 12 2,338,181 1/1944 Holden 335112 2,339,472 1/1944 Frederick 3351l2 3,233,050 2/1966 McKee 335112 BERNARD A. GILHEA-NY, Primary Examiner. H. BROOME, Assistant Examiner. 

